Constant lane-switching, which is inevitable while driving on a busy highway, has been causing greater inconvenience for a driver of a motor vehicle today than five years ago, and it goes without saying that the situation will aggravate in the next five years due to the rapidly increasing number of cars which make the already crowded highway system, especially around metropolitan, or densely populated urban areas become more crowded. As a result, while driving in highway zones like that, a driver has to constantly turn his/her head around to look backward at what is known as the blind spot, a spot neither the interior rearview mirror, nor the exterior side rear-view mirror of a vehicle is able to reflect, to make sure there is not a passing vehicle there before he/she switches to the passing lane.
For the better part of history, automobiles don't have a blind spot mirror to speak of, although accidents caused directly or indirectly due to the failure of noticing the blind spot had concerned the insurance companies, the engineers and designers in the profession for a long period of time, especially since the last quarter of the twentieth century. In more recent years, a round convex mirror known as fisheye was invented to install on top of the side rearview mirror to serve, by using its unique feature of convexity to widen the capacity of a conventional mirror's reflecting coverage, as the blind spot mirror. And upon the invention of this tiny convex mirror an improvement was made and a larger, round convex mirror was built to install on trucks, usually below the exterior side rearview mirror to serve as a blind spot mirror. Since the improved convex mirror was larger than “the fisheye”, its capacity of reflecting coverage was greater than its predecessor's. And a relatively smaller round convex mirror was consequently made to attach on top of the exterior side rearview mirror by means of double stick foam adhesive to serve as the blind mirror for smaller vehicles such as family cars, vans, jeeps etc.
Literally, many prior art patents exist in this area of technology which, in theory, should substantially eliminate the blind spot. In reality, however, none of them is able to convince a driver that the blind spot has been completely eliminated, on the contrary, due to the position of the exterior rearview mirror upon which the convex blind mirror was attached, the round convex blind spot mirror, while reflecting images inside the blind spot mirror, will also reflect images which are not in the blind spot. As a result a driver has to discern which one of these images is inside the blind spot and which is not. Moreover, only those bigger vehicles such as trucks and buses have enough room for the installation of a full-sized convex mirror without sacrificing the area of the side rearview mirror, as the exterior convex blind spot mirror can only be installed outside the vehicle, a family vehicle has to sacrifice at least one third of the area of its side rearview mirrors in order to put on an exterior blind spot mirror.
These deficiencies of the exterior blind spot mirror limited its application, while on the other hand the request of the blind spot mirror for automobiles, especially family vehicles whose numbers are increased rapidly in recent years become more urgent. And it is commonly acknowledged that the lacking of a blind spot mirror is one of the most dangerous factors that may cause terrible accidents on highways.
Clearly, the invention of the exterior convex blind spot mirror is the advancement in the area of safety to the drivers under heavy traffic circumstances, yet this advancement is only applicable to bigger vehicles such as trucks, buses which have enough room below the side rearview mirror for the installation of the exterior convex blind spot mirror. That is, an exterior convex blind spot mirror is only effective when it is used properly for bigger vehicles, although, of course, due to the limitation of its position, the exterior convex blind spot mirror doesn't provide for a driver of a bigger vehicle with a complete view when a small vehicle passes by.
Since such an advancement is not properly done, a small-sized vehicle such as a family car, a van, or a pick-up etc. still suffers the inconvenience caused by the blind spots.
A number of blind spot mirrors have been developed which attempt to properly eliminate the blind spots. Examples of this prior art of blind spot mirrors include U.S. Pat. No. 4,182,552 discloses a composite mirror assembly adapted to be mounted adjacent the driver of a vehicle to enable the driver to view objects within an area normally hidden from view by conventional vehicle mirrors. An additional mirror is positioned at an angle with respect to the conventional side mirror.
U.S. Pat. No. 4,200,359 discloses a small, flat mirror being mounted through use of a wedge-shaped adhesive block to the inside portion of a conventional side view mirror. The block positions the small mirror at an angle of about 15 degrees to 20 degrees with respect to the plane of the side view mirror to thereby eliminate the blind spot.
U.S. Pat. No. 5,044,739 discloses a smaller auxiliary convex mirror mounted on a larger mirror so that the smaller auxiliary convex mirror may be tilted to a limited extent to more precisely position the wide angle field of view it provides. The convex mirror is attached to a tilting plate by an adhesive means, and the tilting plate has a central projecting member with a cavity. A support plate attached to the smooth base mirror by another adhesive means has a corresponding central bar with a spherical head which engaged in the cavity of the tilting plate so that the convex mirror and tilting plate are pivotable.
U.S. Pat. No. 5,566,028 discloses an apparatus, which exposes the blind spot in the direction in which a vehicle makes a turn, to be installed at the back of mechanically or electrically operated side rearview mirrors. A mechanical device, connected to a mirror unit and to the frame, having a diaphragm sealingly disposed therein. When a winker switch is activated, the diaphragm housing is activated by vacuum, causing the diaphragm to be sucked backwards, resulting in said mirror unit pivoting backwards to expose the blind spot . . .
U.S. Pat. No. 6,076,934 discloses a vehicle blind spot mirror with a mirror having a single plane outwardly curved surface, and extension member attached to the rear portion of the outwardly curved mirror and having a double stick foam tape attachment means on the opposite surface of the extension, allowing the extension and attached blind spot mirror to be affixed to a vehicle's existing rearview mirror even if the rear view mirror is set in a recessed frame, thereby allowing for a larger blind spot mirror than the original rearview mirror.
U.S. Pat No. 6,523,965 discloses an improved mirror for use on most types of motor vehicles (cars and trucks) includes two flat reflecting surface used as the principal rearview mirror, and a second reflecting surface being oriented so as to provide a reflected image of traffic in the blind spot mirror. A support structure holds the principal reflecting surface bound to the larger reflecting surface, the blind spot mirror. Although the blind spot mirror is larger, only portions of it appear to the driver as it is mostly covered by the principal reflecting surface. The support structure between the two reflective surfaces has the shape of a wedge necessary for maintaining the blind spot mirror at the proper angle so as to reflect blind spot traffic to the eye of the driver.
Although these prior art blind spot mirror units are adequate for the purpose for which they were intended, these devices either fail to completely eliminate the blind spot or cast the intactness of the side rearview mirror by taking a considerable portion of the side rearview mirror for the attachment of the blind spot mirror. The conventional side rearview mirror of the driver's side, which is just big enough for a driver of a vehicle to view objects within that angle, will become rather ineffective even if a quarter of it is taken for the installation of the blind spot mirror, leave alone the possibility of visionary confusion, such as broken, fragmental images in both mirrors, that the combination of the two mirrors will cause.
Therefore, the prior art blind spot units are only suitable for a bigger vehicle such as a truck, a school bus that has enough rooms below the side rearview mirrors on either side of the driver for the installation of the blind spot mirror units. It would obviously be preferable to provide a more effective, flexible device for smaller vehicles to eliminate the blind spot without sacrificing the conventional side rearview mirrors.